Archceolithothamnium affine n. sp. 



FIG. 1. Photograph of part of an obliquely transverse section (Antigua, T. W. Vaughan, Sta- 

 tion No. 6873), from branch at left as shown in fig. 1, plate 4), enlarged 44 diameters. 



FIG. 2. Photograph of a part of an obliquely transverse section (Antigua, T. W. Vaughan, Sta- 

 tion No. 6888), enlarged 72 diameters. 



